* src/eval.c (backtrace_p, backtrace_top, backtrace_next): Export them to
.gdbinit.
* src/data.c (pure_write_error): Add `object' argument.
* src/puresize.h (CHECK_IMPURE): Use it.
* src/keyboard.c (safe_run_hooks_error): Improve error message.
* lisp/emacs-lisp/lisp-mode.el (eval-sexp-add-defvars): Expand macros
eagerly.
* lisp.el: Provide completion of locally bound variables in Elisp.
* lisp/emacs-lisp/lisp.el: Use lexical-binding.
(lisp--local-variables-1, lisp--local-variables): New functions.
(lisp--local-variables-completion-table): New var.
(lisp-completion-at-point): Use it to provide completion of let-bound vars.
Update instructions in nt/INSTALL.MSYS.
Attempt to resolve gettimeofday compilation errors with MinGW64.

 src/w32.c (gettimeofday): Make the signature identical to prototype
 in nt/inc/sys/time.h.

 nt/inc/sys/time.h (struct timeval): Remove the _W64 guards.
* eshell/em-term.el (cl-lib): Require `cl-lib'.
Fix minor problems found by static checking.

* data.c (pure_write_error):
Use xsignal2, not Fsignal, as Fsignal might return.
* eval.c (set_backtrace_debug_on_exit): Now static.
(backtrace_p, backtrace_top, backtrace_next, record_in_backtrace):
No longer inline.  EXTERN_INLINE is needed only for functions
defined in .h files.  Reindent function header as per GNU style.
(backtrace_p, backtrace_top, backtrace_next):
Mark EXTERNALLY_VISIBLE so they don't get optimized away by the
compiler or linker.  Add extern decls to pacify gcc -Wall.
* frame.c, frame.h (Qgeometry, Qworkarea, Qmm_size, Qframes, Qsource):
Now static.
* frame.c (free_monitors): Define only on platforms that need it.
* nsterm.m (ns_term_init):
* process.c (catch_child_signal):
Don't worry about whether SIGCHLD is defined, as SIGCHLD is
defined on all porting targets these days.
* process.c, process.h (catch_child_signal):
Make it extern only if NS_IMPL_GNUSTEP is defined.
Add HAVE_GLIB check instead of checking individual libraries that use GLib.

* configure.ac (HAVE_GLIB): Add GLib check.  Set XGSELOBJ if GLib is
used.  Remove xgselect.o from XOBJ.

* src/Makefile.in (XGSELOBJ): New, xgselect.o if GLib is used, or empty.

* src/process.c (wait_reading_process_output): Call xg_select if HAVE_GLIB.

* src/xgselect.c: Replace #if defined ... with #ifdef HAVE_GLIB.
* configure.ac (HAVE_GFILENOTIFY): Do not change $LIBS.
(GFILENOTIFY_CFLAGS, GFILENOTIFY_LIBS): Substitute.

* nt/config.nt: Add HAVE_GFILENOTIFY, HAVE_W32NOTIFY and USE_FILE_NOTIFY.

* src/Makefile.in (GFILENOTIFY_CFLAGS, GFILENOTIFY_LIBS): New variables.
(ALL_CFLAGS): Add $(GFILENOTIFY_CFLAGS).
(LIBES): Add $(GFILENOTIFY_LIBS).

* src/w32inevt.c (handle_file_notifications): Add dummy implementation
for !HAVE_W32NOTIFY.

* src/w32term.c: Wrap code with HAVE_W32NOTIFY.